Why Do Orchestras Tune to an A Note?

When orchestra members tune their instruments before a performance, it almost always sounds the same. That’s because across the world, most orchestras tune to the same A note, using a standard pitch of 440 hertz.

This is the result of international standards that have been in place since the 19th century, according to WQXR, a classical music radio station in New York City. Currently, standard tuning frequency is set by the International Organization for Standardization (ISO), an international group that makes recommendations on everything from what safety labels should look like to how big the hole in a pen cap should be. A standard called ISO 16, first recommended in 1955 and confirmed in 1975, “specifies the frequency for the note A in the treble stave and shall be 440 hertz.”

The ISO didn’t pull that frequency out of thin air. During the Industrial Revolution, a rush toward standardization and universality led to multiple international meetings that aimed to bring orchestras all over the world to the same pitch. Standardizing pitch had important ramifications for the international music scene.

Historically, the pitch that orchestras tuned to could differ wildly depending on where the musicians were playing. “In the course of the last 400 years in Europe, the point that has been considered ideal for a reference pitch has fluctuated by some 5 or 6 semitones,” musicologist Bruce Haynes explained in his book, A History of Performing Pitch: The Story of ‘A.’ In the 17th century, a French performer might tune his or her instrument a whole tone lower than their German colleagues. The standards could even change from one town to the next, affecting how music written in one location might sound when played in another.

As a writer for London's The Spectator observed in 1859, “It is well known that when we are performing Handel's music (for example) from the very notes in which he wrote it, we are really performing it nearly a whole tone higher than he intended;—the sound associated in his ear with the note A, being nearly the same sound which, in our ear, is associated with the note G.”

In the 19th century, a commission established by the French government tried to analyze pitch across Europe by looking at the frequencies of the tuning forks musicians used as their reference while tuning their instruments. The commission gathered tuning forks from different cities, finding that most were pitched somewhere around 445 hertz. Over the years, due to bigger concert halls and more advanced instruments, pitch was rising across most orchestras, and instruments and voices were being strained as a result. So the commission recommended lowering the standard to what was known as “the compromise pitch.”

In 1859, the French commission legally established diapason normal, the standard pitch for the A above middle C, at 435 hertz. (The music world would still be debating whether or not pitch had risen too much more than a century later.) Later, 435 hertz became enshrined as a standard elsewhere, too. In 1885, government representatives from Italy, Austria, Hungary, Prussia, Russia, Saxony, Sweden, and Württemberg met to establish their own international standard, agreeing on 435 hertz. The agreement was eventually written into the Treaty of Versailles in 1919.

But not everyone was on board with 435 hertz. The Royal Philharmonic Society in London believed the French pitch standard was pegged to a specific temperature—59°F—and decided to adjust their pitch upward to compensate for their concert halls being warmer than that, settling on 439 hertz. Meanwhile, in 1917, the American Federation of Musicians declared 440 hertz to be the standard pitch in the U.S.

In 1939, the International Standardizing Organization met in London to agree on a standard for concert pitch to be used across the world. A Dutch study of European pitch that year had found that while pitch varied across orchestras and countries, the average of those varied pitches was around 440 hertz. So it made sense for the ISO to choose A 440. Furthermore, radio broadcasters and technicians like the BBC preferred A 440 to the English A 439 because 439 was a prime number and thus harder to reproduce in a laboratory.

World War II delayed the official launch of the 1939 ISO agreement, but the organization issued its A 440 decision in 1955, then again two decades later. A 440 was here to stay. That said, even now, pitch does vary a little depending on the musicians in question. The Vienna Philharmonic Orchestra notably tunes to 443 hertz rather than the standard 440 hertz, for instance. While A 440 may be the official “concert pitch” across the world, in practice, there is still a little wiggle room.

Why Do Bats Hang Upside Down?

The age-old question of upside down bats. Yes, it is awfully weird that there is an animal—a mammal even—that hangs upside down. Sure, some monkeys do it when they're just monkeying around. And a few other tree climbers, like margays, hang upside down if they are reaching for something or—again, like the margay cat—may actually even hunt that way ... But bats are the only animals that actually spend most of their time hanging upside down: feeding this way, raising their young this way, and, yes, sleeping or roosting this way.

There is actually a very good and sensible reason why they do this: They have to hang upside down so that they can fly.

First off, we have to acknowledge that bats are not birds, nor are they insects. These are the other two animals that have true powered flight (as opposed to gliding). The difference between bat flight and bird or insect flight is weight—specifically, the ratio of weight to lift-capacity of the wings. If you walk up to a bird or insect, most species will be able to fly right up into the air from a motionless position, and do it quickly.

Bats, on the other hand (or, other wing), can’t do that. They have a lot of difficulty taking off from the ground (not that they can’t do it ... it’s just more difficult). Insects and birds often actually jump into the air to give them a start in the right direction, then their powerful wings take them up, up, and away.

Birds have hollow bones; bats don’t. Insects are made of lightweight chitin or soft, light tissue; bats aren’t. And bats don’t have what you could call "powerful" wings. These amazing creatures are mammals, after all. The only flying mammals. Nature found a way to evolve such an unlikely thing as a flying mammal, so some compromises had to be made. Bats, once airborne, manage perfectly well in the air, and can literally fly circles around most birds in flight. The problem is in first getting off the ground.

To compensate for the extra weight that mammals must have, to compensate for the problem of getting off the ground, evolution found another way for bats to transition from being motionless to immediately being able to fly when necessary. Evolution said, “How about if we drop them from above? That way they are immediately in the air, and all they need to do is start flapping."

It was a great idea, as it turns out. Except bat feet aren’t any good for perching on a branch. They are mammals, not birds, so their musculature, their bones, and their tendons are set up in a completely different way. When a bird squats down on a branch, their tendons actually lock their toes into an even tighter grip on the perch. It happens automatically. That’s part of being a bird, and is universal. That’s why they don’t fall off in their sleep.

Bats, as mammals, are set up differently. Therefore, to compensate for that fact, nature said, “How about if we have them hang upside down? That way, their tendons will actually pull their toes closed, just like a bird does from the opposite direction.” So that’s what evolved. Bats hang from the bottom of something, and all they have to do is "let go" and they are instantly flying. In fact, with this gravity-assist method, they can achieve instant flight even faster than birds, who have to work against gravity.

Side note: In case you were wondering how bats poop and pee while upside down ... First off, pooping is no big deal. Bat poop looks like tiny grains of rice; if they are hanging, it just falls to the floor of the bat cave as guano. Pee, however ... well, they have that covered too. They just “hold it” until they are flying.

So there you go. Bats sleep hanging upside down because they are mammals and can’t take off into the air like birds can (at least not without difficulty). But, if they're hanging, all they do is let go.

Makes total sense, right?

Now, having said all that about upside down bats, I must mention the following: Not all of the 1240-plus species of bats do hang upside down. There are exceptions—about six of them, within two different families. One is in South America (Thyropteridae) and the other is in Madagascar (Myzopodidae). The Myzopodidae, which includes just one species, is exceedingly rare.

So it turns out that these bats roost inside the tubes of young, unfurled banana leaves and other similar large leaves. When they attach themselves to the inside of this rolled leaf, they do it head-up. The problem with living inside of rolled-up leaves is that within a few days, these leaves will continue growing, and eventually open up. Whenever that happens, the whole group of bats has to pick up and move to another home. Over and over again. All six of these species of rare bats have a suction cup on each wrist and ankle, and they use these to attach to the smooth surface of the inside of the leaf tube. Evolution: the more you learn, the more amazing it becomes.

What's the Difference Between Tequila and Mezcal?

Aside from tacos, enchiladas, and other tasty tortilla-wrapped treats, tequila and mezcal are among some of Mexico’s best-known offerings in the food and beverage category. These tipples, made from the agave plant, are so embedded in the country’s culture that Mexico City even has a museum dedicated to the two drinks, and Jose Cuervo operates a "tequila train" to none other than the city of Tequila. These beverages can be used to make a variety of cocktails, from the tequila sunrise to the mezcalita, but unless you’re a bartender or a connoisseur of spirits, you might not know the difference between the two. Is mezcal just fancier tequila?

Not exactly. Tequila is a type of mezcal, but the reverse isn’t always true. It’s similar to the distinction between champagne and sparkling wine, in which the name of the beverage depends on whether it was produced in the Champagne region of France or elsewhere. While mezcal can be produced anywhere in Mexico, tequila is made in the Mexican state of Jalisco (though a few exceptions do apply).

Tequila and mezcal also differ in the ingredients from which they are derived. Mezcal can come from any of the dozens of agave plants—a type of desert succulent—that are grown throughout Mexico. Tequila is made specifically from blue agave and, depending on the variety and brand, a bottle will contain between 51 percent and 100 percent of the plant-based nectar. According to The Tierra Group, a wholesaler of agave products, blue agave nectar is especially sweet because it’s 80 percent fructose, per Mexico’s regulations.

Lastly, tequila and mezcal taste different because of the ways in which they are prepared. Mezcal tends to have a savory, smoky, earthy flavor because the agave hearts (or piñas) are left cooking for several days in a fire pit that has been lined with volcanic rock and covered with agave leaves and earth. The piñas destined to end up in tequila, on the other hand, are often cooked in a brick oven, then crushed up to extract the juice.

If you ever feel adventurous at the liquor store and decide to bring home a bottle of mezcal, just keep in mind that there’s a particular way to drink it. “The first mistake many people make is pouring mezcal in a shot glass and pouring it down their throat,” Chris Reyes, a mixologist at New York City’s Temerario bar and restaurant told Liquor.com. Instead, the spirit is best sipped in a clay cup known as a jicarita.

Some words of advice if you do go shopping for mezcal: If you ever see a worm at the bottom of the bottle, that means it’s probably not a very good mezcal, according to Reyes. By contrast, tequila bottles should never have worms in them (despite the common misconception). So if you’re looking to avoid invertebrate-infused concoctions at all costs, tequila is your best bet.